首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   178313篇
  免费   32716篇
  国内免费   2467篇
耳鼻咽喉   5417篇
儿科学   6053篇
妇产科学   2995篇
基础医学   6645篇
口腔科学   2374篇
临床医学   29492篇
内科学   52443篇
皮肤病学   7799篇
神经病学   17465篇
特种医学   7435篇
外科学   43832篇
综合类   539篇
现状与发展   72篇
一般理论   31篇
预防医学   9863篇
眼科学   4039篇
药学   3328篇
中国医学   49篇
肿瘤学   13625篇
  2024年   690篇
  2023年   4860篇
  2022年   1326篇
  2021年   3408篇
  2020年   6234篇
  2019年   2549篇
  2018年   7812篇
  2017年   7666篇
  2016年   8754篇
  2015年   8836篇
  2014年   16162篇
  2013年   16797篇
  2012年   7255篇
  2011年   7387篇
  2010年   11347篇
  2009年   15235篇
  2008年   7650篇
  2007年   6117篇
  2006年   8564篇
  2005年   5772篇
  2004年   5028篇
  2003年   3906篇
  2002年   3952篇
  2001年   4015篇
  2000年   3146篇
  1999年   3453篇
  1998年   4025篇
  1997年   3776篇
  1996年   3646篇
  1995年   3456篇
  1994年   2177篇
  1993年   1808篇
  1992年   1501篇
  1991年   1559篇
  1990年   1177篇
  1989年   1296篇
  1988年   1123篇
  1987年   966篇
  1986年   980篇
  1985年   856篇
  1984年   747篇
  1983年   667篇
  1982年   747篇
  1981年   635篇
  1980年   582篇
  1979年   410篇
  1978年   429篇
  1977年   499篇
  1975年   340篇
  1972年   327篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
A case of Goldenhar’s Syndrome in a 10 year old girl is reported. The unusual features are the absence of epibulbar dermoid which is one of the major hallmarks of the Syndrome and the presence of an associated Cyanotic Heart disease.  相似文献   
105.
106.
Obese Zucker rats are less responsive than their lean littermates to the effects of cholecystokinin-octapeptide on satiety and pancreatic growth and exocrine function. We hypothesized that the hyperphagia observed in obese Zucker rats may be caused by a decreased pyloric contractile response to cholecystokinin, resulting in an increased rate of gastric emptying, decreased postprandial gastric distention, and thus decreased satiety. Pyloric muscle strips from six obese Zucker rats and six lean littermates were mounted in separate tissue baths and isometric contraction was measured in response to acetylcholine and cholecystokinin-octapeptide. The dose-response curves for acetylcholine-and cholecystokinin-octapeptide-stimulated pyloric muscle contraction were similar for both the obese and the lean rats. (For cholecystokinin, D50 obese=4.0±0.6 nM, D50 lean=3.4±0.2 nM;P=0.16). We conclude that the decreased satiety response to cholecystokinin-octapeptide observed in obese Zucker rats is not secondary to a decreased pyloric responsiveness to cholecystokinin.This work was supported by NIH grant AM28303-03.  相似文献   
107.
108.
109.
Phytochemical-mediated modulation of P-glycoprotein (P-gp) and other drug transporters may give rise to many herb-drug interactions. Serial plasma concentration-time profiles of the P-gp substrate, digoxin, were used to determine whether supplementation with goldenseal or kava kava modified P-gp activity in vivo. Twenty healthy volunteers were randomly assigned to receive a standardized goldenseal (3210 mg daily) or kava kava (1227 mg daily) supplement for 14 days, followed by a 30-day washout period. Subjects were also randomized to receive rifampin (600 mg daily, 7 days) and clarithromycin (1000 mg daily, 7 days) as positive controls for P-gp induction and inhibition, respectively. Digoxin (Lanoxin, 0.5 mg) was administered p.o. before and at the end of each supplementation and control period. Serial digoxin plasma concentrations were obtained over 24 h and analyzed by chemiluminescent immunoassay. Comparisons of area under the curve (AUC)((0-3)), AUC((0-24)), C(max,) CL/F, and elimination half-life were used to assess the effects of goldenseal, kava kava, rifampin, and clarithromycin on digoxin pharmacokinetics. Rifampin produced significant reductions (p < 0.01) in AUC((0-3)), AUC((0-24)), CL/F, t(1/2), and C(max), whereas clarithromycin increased these parameters significantly (p < 0.01). With the exception of goldenseal's effect on C(max) (14% increase), no statistically significant effects on digoxin pharmacokinetics were observed following supplementation with either goldenseal or kava kava. When compared with rifampin and clarithromycin, supplementation with these specific formulations of goldenseal or kava kava did not appear to affect digoxin pharmacokinetics, suggesting that these supplements are not potent modulators of P-gp in vivo.  相似文献   
110.
Chemoprevention refers to suppression or reversal of the carcinogenic process using pharmacologic or nutritional agents. Colorectal carcinogenesis is a protracted, multistep process that offers opportunities for prevention. Aspirin and selective cyclooxygenase-2 inhibitors (coxibs) have been evaluated for the prevention of sporadic adenoma recurrence. Aspirin was shown to reduce adenoma recurrence rates in patients with prior colorectal neoplasms; however, the optimal dosage remains unclear. Recent studies of coxibs indicate that these agents are effective in reducing sporadic adenoma recurrence, but chronic use can result in serious cardiovascular toxicity. These data underscore the need for chemopreventive agents with acceptable risk-to-benefit ratios. In this regard, nitric-oxide-releasing aspirin shows chemopreventive efficacy in preclinical models and holds promise for reduced toxicity in humans. Furthermore, ongoing chemoprevention trials are evaluating nutritional supplements, such as folic acid and selenium, and results are eagerly awaited.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号